Hi;
looking for help. how do i replace a thermostat on my 1985 300sd. does it require special tools . any help would be appreciated.

my email tcumb@yahoo.com
thank you

With the car cold look for the thermostat cover. Follow the left radiator hose from the radiator to the block. Where the left radiator hose attaches to the block is the thermostat cover. Remove the three 10mm fasteners, pull the cover toward the radiator and you should find the thermostat. Pay attention to the orientation of the thermostat inside the housing to insure you install the new one the same way the old one comes out. Install an new rubber "o-ring" seal around the thermostat, install the new thermostat, put the cover back on and install/tighten the 10mm fasteners. Don't overdo it when you tighten the fasteners or you will regret it. The hardest part will be filling the system back up with water/coolant. The way I do it is to remove the radiator hose on the right hand side from the radiator, fill with the mixture with the hose held down "low" and then raise the end of the hose. You will know you have the system full when the level quits disappearing in the hose then you can just reattach the hose.
Come back if you have more questions.

__________________
Jim

If you thermostat housing has a bolt on top with a 10 mm head with a washer.. Remove the screw to fill... If not fill slow.. I always just put it all together.. then fill... After you fill it wait a while to see that it stays full.. when you start the car let it warm ... Watch the water level.. Turn the Heat on high or defrost on.. It will also needs to pump any air from the heat system..

Ken

To Jim & Ken:
this is tcumb with the 300sd with the thermostat problem, I followed your advice and corrected the problem. Just wanted to say than you. will probably seek other solutions from the forum in the near future.

thanx
Tony C.